Sometime afterwards, Michael went out into the jungle to search for his son, Walt. However, he was soon captured by the Others. While in their captivity, Danny Pickett approached him, taking a blood sample from him. It is unknown what became of this blood sample or how it was used, but it is most likely it was taken to run a paternity test on Michael, as Bea Klugh began asking him questions soon afterward. ("Three Minutes")

The most recent occurrence of blood samples being taken was from Jack, Kate, and Sawyer when they were captured by the Others and taken to the Hydra. Though the act of taking the samples was never seen on-screen, all three characters found bandages on their arms soon after awakening at their places of imprisonment. It is unknown what the blood was used for. ("A Tale of Two Cities")